Opticians are placing before hundreds of thousands simple truths about the eye not otherwise taught as yet.
Whether opticians and physicians are unprofessional or unethical may be told by reëxamination if the examiner is himself competent and ethical.
So naturally do we associate eyeglasses with eye defects that some people assert that the eye tests at school originate with opticians more intent upon selling spectacles than upon helping children.
Baker, 244, High Holborn; and we mention them, not because we wish to make any invidious distinctions between the many excellent opticians who now make microscopes, but because we happen to have used Messrs.
The slides containing the objects usually shown in a magic lantern, are to be bought at opticians with the lantern, and can be procured cheaper and better in this way than by any attempt at manufacturing them.
Rotherfield Street, Islington, London, and of Chemists and Opticians everywhere.
The opticians sell special pieces of apparatus for this purpose, but though they are very useful, they do not render it less desirable to have the mirror mounted as described.
As time has gone on, astronomers and opticianshave invented new, and more perfect, and more luxurious instruments.
No fabric of human construction is fine enough to strain across the eyepiece of an important telescope, and opticians preserve a particular race of spiders, that their webs may be taken for that purpose.
But the discovery that the dispersive powers of different glasses are not proportional to their reflective powers, supplied opticians with the means of remedying the defect.
If damp gets between the glasses it produces a fog (which opticians call a sweat) or even a seaweed-like vegetation, by which a valuable glass may be completely ruined.
But later opticians have found means of correcting these imperfections, so that we are now able to use object-glasses a foot or more in diameter, which give very clear and bright images.
This principle, employed by the boy with his cross-staff in 1564, is employed at the present day by the Astronomer Royal at Greenwich with the most superb instruments that the skill of modern opticians has been able to construct.
I think it is Professor Piazzi Smith who tells us how grateful he was to find a large telescope he had ordered finished by the opticians on the very day they had promised it.
Islington, London, and of Chemists and Opticians everywhere.
Metius, a professor of mathematics, and Jansen and Lipperhey, who were opticians in Middelburg--all three are entitled to consideration as claimants of the original invention of the telescope.
These two aberrations, spherical and chromatic were the principal faults that opticians had to deal with, because they affect the whole of the image, even the very central parts.
By the use of these newer glasses the limitations that had previously restricted opticians were removed, and it became possible to correct astigmatism and secure a flat field at the same time.
The one aim of opticians in improving photographic lenses has been to get good definition all over a comparatively large flat surface without having to use small apertures.
Opticians had given up, more from theory than from careful experiments, attempting high magnifying powers, even for reflecting telescopes.
Some of the English opticians have shown that very portable, and really accurate barometers can be made in brass frames, and therefore the preference is now given to this latter material.
BLAND & LONG, Opticiansand Photographical Instrument Makers, and Operative Chemists, 153.
Opticians are thus sure to be caught on one of the horns of a dilemma; either they do not use drops to paralyze the ciliary muscle, or, if they do employ the drops, they may do irreparable damage to the eye.
Opticians are incompetent to employ these drops, as they may do great damage in certain conditions of the eye which can only be detected by a medical man specially trained for such work.
The speculum was carefully placed aside after its cleansing, and the pair of amateur opticians locked up the place after hanging up their aprons.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "opticians" in a variety of sentences. We hope that you will now be able to make sentences using this word.
